A portable readout system for microstrip silicon sensors
A portable readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain A portable readout system for microstrip silicon sensors (ALIBAVA) Bernabeu, J. a, Casse, G. b, García, C. a, Greenall, A. b, Lacasta, C. a, Lozano, M. c, Marco-Hernández, , R. a, Martí i García, S. a, Martinez, R. b Miñano, M. a, Pellegrini, G. c, Smith, N. A. b, Ullán, M. c a b Instituto de Física Corpuscular (IFIC), Universidad de Valencia-CSIC, Valencia, Spain. Department of Physics, Oliver Lodge Laboratory, University of Liverpool, UK. c Instituto de Microelectrónica de Barcelona, IMB-CNM, CSIC, Barcelona, Spain Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 1
A portable readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Outline • • Motivations. System requirements. System architecture. Daughter board: – Block diagram. – Beetle chip. – Fan-ins. • Mother board: – Block diagram. – FPGA logic. – System operation. • • • PC software characteristics. Calibration measurements. Measurements with laser setup. Measurements with β source. Conclusions and outlook. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 2
A portable readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Motivations • • • Study the main properties of highly irradiated microstrip silicon sensors: SLHC. Particularly the collected charge: detector performance. Difficulty for obtaining this type of measurements: – Required equipment is expensive. – A large number of channels has to be measured. – There is minimum standardization. Testing with an electronic system as similar as possible to those used at LHC experiments: a LHC front end readout chip should be used. Analogue readout is preferred for accurate pulse shape reconstruction. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 3
A portable readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain System requirements • • • A compact and portable system. The system will be used with two different laboratory setups: – Radioactive source: external trigger input from one or two photomultipliers. Alternatively a digital trigger input as well (from an external discriminator). – Laser system: synchronized trigger output generated internally for pulsing an external excitation source. The system should contain two front-end readout chips (Beetle chip used in LHCb) to acquire the detector signals. USB communication with a PC which will store and will process the data acquired. System control from a PC software application in communication with a FPGA which will interpret and will execute the orders. Own supply system from AC mains. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 4
A portable readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain System requirements • • • A compact and portable system. The system will be used with two different laboratory setups: – Radioactive source: external trigger input from one or two photomultipliers – Laser system: synchronized trigger output generated internally for pulsing an external excitation source. The system should contain two front-end readout chips (Beetle chip used in LHCb) to acquire the detector signals. USB communication with a PC which will store and will process the data acquired. System control from a PC software application in communication with a FPGA which will interpret and will execute the orders. Own supply system from AC mains. The main goal is reconstructing the analogue pulse shape from the readout chip front-end with the highest fidelity from the acquired data. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 5
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain System architecture • • Two main parts: software part (PC) and hardware part. Hardware part: a dual board based system. – Mother board intended: • To process the analogue data that comes from the readout chips. • To process the trigger input signal in case of radioactive source setup or to generate a trigger signal if a laser setup is used. • To control the hardware part. • To communicate with a PC via USB. – Daughter board : • It will be a small board. • It will contain two Beetle readout chips • It will have fan-ins and detector support to interface the sensors. • Software part: – It will control the whole system (configuration, calibration and acquisition). – It will generate an output file for further data processing. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 6
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Daughter board: block diagram • • Two Beetle readout chips in parallel mode (256 input channels). A buffer stage for each analogue output of the Beetle chips: – Differential current to differential voltage buffer (AD 8132) implemented. – Buffered signals are sent to the mother board with impedance matched. • • • Fast control (LVDS signals) and slow control (I 2 C bus) shared by Beetle chips. A thermistor (NTC) for sensing the temperature close to the Beetle chips. Low voltage DC level (5 V) for Beetle chips (2. 5 V) and buffer stage power supply (3 V). High voltage DC level for silicon detector(s) bias through a power lemo connector. Fan-ins and detector board. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 7
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Daughter board: Beetle chip • • Readout chip developed at ASIC laboratory of the University of Heildelberg. Front-end output signal: signal that will be reconstructed from analogue readout onto one port. • This signal is sampled into the analogue pipeline (128 x 187 cells) with the frequency of the Beetle chip clock (40 MHz). • Vp = k. Q. Tp ~ 25 ns. Total pulse length about 65 -70 ns. • The analogue pipeline programmable latency fixed to 128 CLK cycles (3. 2 µs). • The TRIGGER signal will have to be active 128 CLK cycles (3. 2 µs) after a particular front-end signal point of interest has been sampled. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 8
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Daughter board: Beetle chip output format • • • Analogue output format: single readout onto one output port. Readout: 16 bits header + 128 analogue multiplexed channels. Channel width of 25 ns (40 MHz clock). Data. Valid signal for readout detection. Output dynamic range: linear up to ~ ± 110000 e-. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 9
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Daughter board: detector support • Fan-ins: – Three fan-ins: chip fan-in, intermediate fanin and detector fan-in. – Each fan-in has pads of 80 um pitch not staggered and 10 rows for multiple wire bonding. • Text-box: – Daughter board and detector boards are fixed to base plate for facilitating wirebonding. • Two flavours of detector board exist: – Small, for 1 cm 2 sensors (board dimensions ~37 mm x 32 mm). – Large, for 1 cm x 3 cm sensors (board dimensions ~37 mm x 50 mm). Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 10
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: block diagram • • Signal conditioning block transforms the differential voltage analogue input signal from each Beetle to: – Drive an oscilloscope: single ended signal. – Drive ADC: differential input shifted signal. ADC (one for each Beetle): – 10 bit flash type with a sample rate of 40 MHz (MAX 1448). – Nominal resolution of 1 m. V (output signed code, 9 bits plus 1 sign bit). – Dynamic range will be ± 512 m. V. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 11
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: block diagram • • • In case of radioactive source setup for obtaining a time stamp of each trigger. Trigger conditioning: – Leading-edge discrimination for two photomultiplier analogue input signals. – Level conversion for an auxiliary signal (current or voltage). – Two dual LVPECL high speed comparators (MAX 9601). – Four programmable voltage thresholds: generated with a quad 12 bits DAC (DAC 7614). TDC: measurement of t between input trigger and a periodic reference signal (100 ns). – A TDC integrated circuit (TDC-GP 1). – Nominal resolution: 600 ps. – 100 ns dynamic range. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 12
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: block diagram • • In case of laser setup. A synchronised output trigger signal (TRIG OUT) will be generated to drive a laser source to reconstruct the Beetle front-end pulse shape. Programmable delay circuit (3 D 7428): – Resolution: 1 ns. – Range: up to 255 ns. – Programmed by FPGA by serial interface. Following this block a 50 Ω driver will be incorporated for driving a pulse generator input. Programmable delay Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 13
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: block diagram • • • SDRAM (256 Mb): for acquisition data storage. TEMPERATURE CONVERTER: NTC thermistor signal digitalization. SLOW CONTROL: generated directly by the FPGA. External pull-up resistors for SDA and SCL lines. FAST CONTROL: – LVDS driver (DS 90 LV 47 A) and LVDS receiver (DS 90 LV 48 A). – Six CM noise suppressor chokes (23 Z 105 SM). USB: USB controller (FT 245 R) for USB to FIFO parallel (8 bits) bidirectional data transfer. SUPPLY SYSTEM: – DC input (5 V) from AC adapter. – Digital levels from 2 DC-DC converter (1. 2 V and 3. 3 V) + 1 linear regulator (2. 5 V). – Analogue levels from DC-DC converter (± 5 V) + 1 linear regulator (3. 3 V). – Daughter board level from DC-DC converter (5 V). Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 14
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: FPGA logic • FPGA hardware: • FPGA logic operation: • FPGA logic blocks: – Xilinx Spartan-3 (XS 3400 -PQ 208) clocked at 40 MHz. – External reset push button. – On-system configuration PROM memory. – Two LEDs for system status. – Custom logic blocks (VHDL) for low level hardware control. – Centralized control from a CFSM. – A CFSM (Central Finite State Machine) will control the different blocks depending on the current state of the system. – Radioactive source: the DAC CONTROL, TRIGGER IN and TDC CONTROL will be used for processing the trigger inputs and obtaining a time stamp of each trigger. – Laser setup: the TRIGGER OUT block will generate the output trigger signal and will control the programmable delay circuit. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 15
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: FPGA logic • FPGA logic blocks: – ADC CONTROL: readout of the digitized data frames when the input Data. Valid (fast control) signal will be active. This digitized data will be stored in a internal FIFO RAM. – BEETLE FAST CONTROL: generation of fast control signals (Clk, Trigger, Testpulse and Reset) depending on the state of the system. – BEETLE SLOW CONTROL: I 2 C master controller for writing/reading the Beetle internal registers (slow control) for configuration. – SDRAM CONTROL: implements a controller for interfacing the SDRAM and the CFSM. – USB CONTROL: interface between the USB controller and the CFSM. – CLOCK GENERATOR: required internal clock and reset signals generation. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 16
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: FPGA logic • FPGA logic: • The functionality of the system is programmed as a standard C program in the processor (firmware): great flexibility for changes. – The CFSM and SDRAM CONTROL have been implemented with an embedded system (soft processor + SDRAM peripheral). – Soft processor: Microblaze (32 bits RISC) at 40 MHz. – SDRAM controller included as standard peripheral for the Microblaze. – ARBITRER : custom block of registers for communication between the embedded processor and the custom logic blocks. – FSLs (Fast Simplex Links): unidirectional FIFOs for fast communication between the ARBITRER and the Microblaze. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 17
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: system operation • • • RESET: – System initialization. – With a power on, with an external reset or by software reset. WAITING: – The system will wait for an order coming from the PC software to go to another state. BEETLE CONFIGURATION: – Beetle chips configuration registers programming. CALIBRATION: – System calibration by the Beetle internal test pulse generator. – Known amplitude readouts will be acquired. TRIGGER IN CONFIGURATION: – DAC voltage thresholds will be programmed. – Trigger inputs scheme will be configured. LASER SYHRONIZATION: – The system will be synchronized for the Beetle front end pulse reconstruction. – By delaying the TRIG OUT signal in 1 ns steps. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 18
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Mother board: system operation • • PEDESTALS, RS or LASER ACQUISITION: – A programmable number of readouts will be able to be acquired (up to 64776) and stored in the SDRAM. – PEDESTALS: For each event a Beetle chips readout (256 by 16 bits) and a temperature readout will be stored in the SDRAM. No charge acquired with Beetle chips. – RS: For each event a Beetle chips readout (256 by 16 bits), a TDC readout (32 bits) and a temperature readout will be stored in the SDRAM. – LASER: For each event a Beetle chips readout (256 by 16 bits) and a temperature readout (16 bits) will be stored in the SDRAM. The TRIG OUT frequency will be 1 KHz. PEDESTALS, RS or LASER READING: – The last type of acquisition will be read from SDRAM and data will be sent to PC by USB. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 19
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain PC software • • • Functions: – Control the whole system (configuration, calibration and acquisition). – User interface with the system (GUI). – Generation of information (output files). Two software levels: – Low level for software/mother board communication by USB: VCP (virtual com port) driver (2. 4 Mb/s) used. – High level: GUI and output file generation for further processing. Programming language: C++ Operating system compatibility: – Linux version fully operational. – Windows beta version. There also macros for ROOT in order to process the data acquired with the software. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 20
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Calibration measurements: n-type detector • • • Data acquired from calibration acquisition. Beetle chip 1 (channels 1128) without detector. Non-irradiated n-type detector connected to Beetle chip 2 (channels 129 -256). First 14 and last 14 channels of Beetle 2 without detector: detector of 100 channels. Some channels does not operate due ‘shorts’ at the bonds: reduced gain. This data is used to calculate the ADC/electrons rate for each channel. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 21
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Calibration measurements: p-type detector • • Data acquired from calibration acquisition. Beetle chip 1 (channels 1128) without detector. Non-irradiated p-type detector connected to Beetle chip 2 (channels 129 -256). This data is used to calculate the ADC/electrons rate for each channel. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 22
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Measurements with laser setup: n-type detector • • • Data acquired by means of a laser scan. Non-irradiated n-type detector connected to Beetle chip 2 (same conditions as on calibration). Vbias = 200 V (full depletion). Laser light: • Laser scan: • Some channels does not work due to bad bonds. • – Wavelength: 1060 nm (near infrared). – Laser energy of photons: 1. 17 e. V. – Scan delay range: 10401140 ns. – Delay step: 1 ns. – 100 samples per step. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 23
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Measurements with laser setup: p-type detector • • • Data acquired by means of a laser scan. Non-irradiated p-type detector connected to Beetle chip 2 (same conditions as on calibration). Vbias = -100 V (full depletion). Laser light: • Laser scan: • All channels work correctly. • – Wavelength: 1060 nm (near infrared). – Laser energy of photons: 1. 17 e. V. – Scan delay range: 10401160 ns. – Delay step: 1 ns. – 100 samples per step. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 24
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Measurements with β source: n-type detector • • • Acquisition with β source (90 Sr). Non-irradiated n-type detector connected to Beetle chip 2 (same conditions as calibration). Vbias = 200 V (full depletion). Acquisition of ~ 19000 events (triggers): – Trigger input from one photomultiplier. – Threshold: -40 m. V. Some channels are noisy due to bad bonds. Pulse peak charge corresponding ~ 1 mip (24810 e-). Noise: ~ 1200 e-. Common mode variations (σ = 5. 88 counts) corrected by software. SNR for peak voltage: ~ 21. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 25
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Measurements with β source: p-type detector • • • Acquisition with β source (90 Sr). Non-irradiated p-type detector connected to Beetle chip 2 (same conditions as calibration). Vbias = -100 V (full depletion). Acquisition of 20000 events (triggers): – Trigger input from one photomultiplier. – Threshold: -40 m. V. All channels working. Pulse peak charge corresponding ~ 1 mip (26940 e-). Noise: ~ 1200 e-. Common mode variations (σ = 8. 9 counts) corrected by software. SNR for peak voltage: ~ 22. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 26
A readout system for microstrip silicon sensors (ALIBAVA) 3 th Workshop on Advanced Silicon Radiation Detectors, 14 -16 April, Barcelona, Spain Conclusions and outlook • • The readout system has been developed and is fully operational. The system can operate with different types and different sizes of microstrip detectors: – – n-type. p-type. Up to 256 input channels. Two flavours of detector boards to accommodate detectors of different sizes. The system is designed to work with a radioactive source setup and laser setup: useful for comparing results with the same detector. The system has been tested with laser setup and a β source: – – – It works correctly. With p-type and n-type detectors. SNR ~ 20 with non-irradiated detectors: there is room for irradiated detectors. Currently, there is a software Linux version: in the near future, there will be a Windows version for the software (currently debugging a beta version). Data acquired with the system can be easily processed using ROOT framework: some macros already developed. System is ready for production and distribution (motherboards and daughterboards in stock). Production and assembly under demand. Future work: upgrade of the system for testbeam acquisition by synchronizing various ALIBAVAs. Ricardo Marco-Hernández IFIC(CSIC-Universidad de Valencia) 27
- Slides: 27